The invention relates to a receiving unit for a circuit board carrier, a connection system, an electric machine with such a receiving unit, and a motor vehicle with such an electric machine.
Electronic control systems for hybrid drives are constructed of function modules and include, for example, an electronic power output stage, an intermediate circuit capacitor, a control printed circuit board, a connecting region, a control unit, a cooling system and a housing.
For example, solderable connections are provided between the individual function modules. These connections are costly to make due to the relatively high driving current.
At the present time solder contacts, weld contacts or screw contacts are used for such connections, in order to connect the circuit board carrier with the electronic power components to the intermediate circuit capacitor and the connecting region by way of bus bars.
The use of bus bars between the circuit board carrier for the electronic power components and the connecting region keeps the handling forces at a distance from the circuit board carrier. The metallurgical connections are characterized by a low contact resistance with simultaneously low space requirement. Screw contacts are compact and allow a standardized handling, and plug-in contacts are easy to install.
The drawback with the metallurgical connections lies in their poor solderability and limited reliability. Screw connections, on the other hand, are associated with high assembly cost and frequent assembly errors and are sensitive to weakening contact forces. Plug-in contacts demand a lot of space and require high plug-in forces for connections with a high current carrying capacity. The pressure contact systems known from the prior art require a lot of space in order to guarantee the force closure (friction locking connection) and are susceptible to assembly errors. In addition, the oxide layers on the contact surfaces degrade contact with the circuit board carrier.
Computer technology discloses plug-in systems, in which a contact guiding printed circuit board is inserted and then clamped by tilting and snap locking (for example, for single inline memory modules (SIMM)).
The use of such plug-in systems is limited to the connection of signal lines due to the low contact forces that can be achieved. The contact surfaces must have a high quality (gold plated), in order to prevent oxidation. The technology used for single inline memory modules has the same disadvantage. In addition, this SIMM technology transmits to the circuit board carrier bending stresses that are in proportion to the contact force and, therefore, is suitable only for systems with low contact forces, that is, low current carrying capacity.
The object of the invention is to avoid the aforementioned drawbacks and to provide, in particular, a receiving unit that allows the circuit board carrier the possibility of an efficient connection with simultaneously a high current carrying capacity.
This and other objects are achieved according to the invention by providing a receiving unit for a circuit board carrier, wherein the receiving unit has at least one electric contact. The circuit board carrier is insertable into the receiving unit at an angle to an end position of the circuit board carrier. The receiving unit is designed such that in the inserted state of the circuit board carrier there are, essentially, no bending forces that act on the circuit board carrier by way of the at least one electric contact.
In particular, it is advantageous that during the insertion of the electric current into the receiving unit, the electric contact is capable of scratching open an oxide layer and, in so doing, ensures that an electric contact is produced. Furthermore, it is advantageous that in the end position of the circuit board carrier, that is, in an inserted state, contact is made with the circuit board carrier in a substantially strainless way.
Another aspect of the invention is that the receiving unit has a recess for receiving a part of the circuit board carrier.
An additional aspect of the invention is that the circuit board carrier can be inserted into the receiving unit along a guide. The guide can help to insert the circuit board carrier at an angle. In particular, it is further developed that the guide includes a guide rail and/or a guide along a housing.
In particular, the housing and/or the receiving unit itself can be constructed so as to help insert the circuit board carrier at an angle into the end position. In this way, it is also possible to efficiently provide for the breaking up of any oxide layer that might be present at the contacts.
It is also a further development that the receiving unit has a plurality of electric contacts that are provided on opposite sides of the circuit board carrier. For example, the contacts may be placed opposite each other. The contacts may also be arranged so as to be at least partially offset in relation to each other.
In this respect it must be pointed out that each contact can be dimensioned as a function of the current flowing through the contact to or from the circuit board carrier. If, for example, a high current flows through the respective contact, then this contact can be dimensioned so as to be suitably large. If the contact serves only to transmit a signal in the low voltage range, then the contact may exhibit small dimensions.
Furthermore, it is a further development that the plurality of electric contacts essentially compensate for the bending forces acting on the circuit board carrier.
In accordance with an additional further development, the opposite side of the at least one contact has a mechanical contact or an electric contact, in order to compensate for the bending forces acting on the circuit board carrier in the inserted state.
In particular, electric or mechanical contacts that are located opposite each other in the end position of the circuit board carrier in the receiving unit lie essentially perpendicular to a conductor track contact surface.
In this respect it must be pointed out that the strainless positioning of the circuit board carrier can also be achieved by means of mechanical contacts. For example, a mechanical contact can be provided by the receiving unit or by means of a housing.
A next further development consists of the fact that the contact is a spring contact. In this case, a wide variety of variations or rather any variation of spring contacts—mechanical and/or electric in nature—are possible.
In one embodiment the receiving unit has a locking mechanism. The locking mechanism serves, in particular, to retain the circuit board carrier in the receiving unit.
An alternative embodiment consists of the fact that the circuit board carrier can be cooled by way of cooling fluid. For example, the cooling fluid may be a coolant or a fluid of the surroundings.
In another embodiment, the circuit board carrier has at least one connection for supplying and/or draining the cooling fluid. In particular, the interior of the circuit board carrier can have a meandering shaped line structure comprising an inflow and an outflow, through which the cooling fluid can flow. It is also an embodiment that the at least one connection for supplying and/or draining the coolant can be combined with the insertion of the circuit board carrier into the receiving unit.
A further development consists of the fact that the at least one electric contact is a contact of a signal line and/or a current line.
It is an additional embodiment that the at least one electric contact is connected to an electric machine. In that regard, the term “electric machine” is defined, in particular, as any electric machine that uses an electromagnetic operating principle. In particular, the electric machine can include an electric motor and/or a generator.
According to the invention, a connection system is provided, which includes the receiving unit described herein and a circuit board carrier for insertion into and/or being received in the receiving unit. Additionally, an electric machine according to the invention is provided that includes at least one receiving unit, as described herein. Still further, a motor vehicle according to the invention is provided with an electric machine as described herein.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.